** 1: UTF8/16 conversion required and function takes any number of arguments.
** 2: UTF16 byte order change required and function takes any number of args.
** 3: encoding matches and function takes any number of arguments
** 4: UTF8/16 conversion required - argument count matches exactly
** 5: UTF16 byte order conversion required - argument count matches exactly
** 6: Perfect match: encoding and argument count match exactly.
**
** If nArg==(-2) then any function with a non-null xStep or xFunc is
** a perfect match and any function with both xStep and xFunc NULL is
** a non-match.
*/
#define FUNC_PERFECT_MATCH 6 /* The score for a perfect match */
static int matchQuality(
FuncDef *p, /* The function we are evaluating for match quality */
int nArg, /* Desired number of arguments. (-1)==any */
u8 enc /* Desired text encoding */
){
int match;
/* nArg of -2 is a special case */
if( nArg==(-2) ) return (p->xFunc==0 && p->xStep==0) ? 0 : FUNC_PERFECT_MATCH;
/* Wrong number of arguments means "no match" */
if( p->nArg!=nArg && p->nArg>=0 ) return 0;
/* Give a better score to a function with a specific number of arguments
** than to function that accepts any number of arguments. */
if( p->nArg==nArg ){
................................................................................
** NULL if the function does not exist.
**
** If the createFlag argument is true, then a new (blank) FuncDef
** structure is created and liked into the "db" structure if a
** no matching function previously existed.
**
** If nArg is -2, then the first valid function found is returned. A
** function is valid if either xFunc or xStep is non-zero. The nArg==(-2)
** case is used to see if zName is a valid function name for some number
** of arguments. If nArg is -2, then createFlag must be 0.
**
** If createFlag is false, then a function with the required name and
** number of arguments may be returned even if the eTextRep flag does not
** match that requested.
*/
................................................................................
pBest->nArg = (u16)nArg;
pBest->funcFlags = enc;
memcpy(pBest->zName, zName, nName);
pBest->zName[nName] = 0;
sqlite3FuncDefInsert(&db->aFunc, pBest);
}
if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){
return pBest;
}
return 0;
}
/*
** Free all resources held by the schema structure. The void* argument points

** 1: UTF8/16 conversion required and function takes any number of arguments.
** 2: UTF16 byte order change required and function takes any number of args.
** 3: encoding matches and function takes any number of arguments
** 4: UTF8/16 conversion required - argument count matches exactly
** 5: UTF16 byte order conversion required - argument count matches exactly
** 6: Perfect match: encoding and argument count match exactly.
**
** If nArg==(-2) then any function with a non-null xSFunc is
** a perfect match and any function with xSFunc NULL is
** a non-match.
*/
#define FUNC_PERFECT_MATCH 6 /* The score for a perfect match */
static int matchQuality(
FuncDef *p, /* The function we are evaluating for match quality */
int nArg, /* Desired number of arguments. (-1)==any */
u8 enc /* Desired text encoding */
){
int match;
/* nArg of -2 is a special case */
if( nArg==(-2) ) return (p->xSFunc==0) ? 0 : FUNC_PERFECT_MATCH;
/* Wrong number of arguments means "no match" */
if( p->nArg!=nArg && p->nArg>=0 ) return 0;
/* Give a better score to a function with a specific number of arguments
** than to function that accepts any number of arguments. */
if( p->nArg==nArg ){
................................................................................
** NULL if the function does not exist.
**
** If the createFlag argument is true, then a new (blank) FuncDef
** structure is created and liked into the "db" structure if a
** no matching function previously existed.
**
** If nArg is -2, then the first valid function found is returned. A
** function is valid if xSFunc is non-zero. The nArg==(-2)
** case is used to see if zName is a valid function name for some number
** of arguments. If nArg is -2, then createFlag must be 0.
**
** If createFlag is false, then a function with the required name and
** number of arguments may be returned even if the eTextRep flag does not
** match that requested.
*/
................................................................................
pBest->nArg = (u16)nArg;
pBest->funcFlags = enc;
memcpy(pBest->zName, zName, nName);
pBest->zName[nName] = 0;
sqlite3FuncDefInsert(&db->aFunc, pBest);
}
if( pBest && (pBest->xSFunc || createFlag) ){
return pBest;
}
return 0;
}
/*
** Free all resources held by the schema structure. The void* argument points